5.4 DOHC build questions

[Mtcrss546]

hey everyone Iv been doing all the research I can and have started my 5.4 dohc build but could use some advice. So far I have a 2003 navigator engine I have it tore down and getting a parts list together. Going to run the stock forged crank, forged rods, windage tray, 7 qt oil pan, ho oil pump, long tubes and all ARP studs and bolts.havent decided on a intake yet. Depends on supercharger style screw or procharger
I'm wanting 700hp. The car will be mostly street and some track it is my second vehicle so econemy is not a concern. So here are my questions to get to this HP goal

1- stock bore? Over bore?
2- compression ratio(supercharger in mind)
3- style/brand pistons
4- recommended cam specs
5- head work? Port polish? Bigger valves?
6- pump gas or e85?
7- injector size

Thanks in advance for all the help and answers!

 

[Sluggie24]

The block itself might tell you if it needs to be bored when checked. Since you're buying pistons anyway I'd say just punch it .020 over and be done.

I can't speak to compression since that is really going to depend on how much boost you want to run and supercharger type.

There are many good pistons out there. You should spend time researching online which ones match your power needs and budget.

Look at what the cam manufacturers offer and call a few up to find the best ones for your combo.

If you will have the heads off port them, polish the chambers and give them a valve job with quality valves and hardware. I don't know if bigger would yield big power gains but if you are putting new ones in anyway won't hurt to bump the size.

Gas is up to you but E85 will allow more aggressive timing and more power.

You will have to do the calculations to figure out injector size once you figure your combo and fuel type out.

I'd also say go with a positive displacement blower to ensure the injectors spray into the runners properly. Using a 4.6 intake with adapters causes issues due to the angle change.

 

[Mtcrss546]

The block does not need to be bored just honed. Was wondering what kind of power increase Boring .020 Would gain roughly. (I know it's not much) if it is worth the extra money or put that money into something else.

I'd like to run a kennel bell Ill have to get a stock terminator manifold that I would widen to fit the 5.4. What size kenne bell and compression ratio would be recommended or ideal for 700hp on the 5.4?

 

[Sluggie24]

If you don't need to bore then don't bother. The power gain isn't big with less than 10ci increase

I'd still say get a supercharger kit designed for the 5.4 so the injectors spray at the correct angle.

I would talk to the supercharger manufacturer you want to find out size and compression since they will know much better than any of us will.

 

[Mtcrss546]

Ya that's the problem no one makes a supercharger kit for a DOHC 5.4

 

[Sluggie24]

You can buy the manifold directly from ford for the GT500.(5.4 DOHC) Get a supercharger kit for the GT500. Then get some missing parts from maybe dept of boost or some place like that to finish the install.